This application claims priority of Austrian Application No. A 1580/2000, filed Sep. 15, 2000, the complete disclosure of which is hereby incorporated by reference.
The invention is directed to tweezers for holding strip-shaped or thread-shaped material with particularly abrasive characteristics, for example, for dental purposes. During intraoral working of tooth fillings and with dental restorations, particularly crowns, which are attached by adhesion, the use of commercially available polishing strips and finishing strips having a width of 5-6 mm as strip-shaped material causes difficulties, primarily with respect to space, especially when a dental dam through which a tooth to be treated protrudes is located inside the oral cavity. This is also true of strips of half-width (2.5-6 mm) and for thread-shaped material.
It is one of the objects of the invention to remedy this difficulty in that clamping elements, particularly in the shape of rods, are arranged in the area of the free end of each of the two sides or legs of the tweezers, wherein, in the closed position of the tweezers, at least one clamping element arranged at a leg contacts two clamping elements arranged at a distance from one another at the other leg or engages in a recess located in the latter.
In particular, in accordance with the invention, tweezers for holding strip-shaped or thread-shaped material with particularly abrasive characteristics, for example, for dental purposes, particularly in the shape of rods, are arranged in the area of the free end of each of the two legs of the tweezers, wherein in the closed position of the tweezers, at least one clamping element arranged at a leg contacts two clamping elements arranged at a distance from one another at the other leg or engages in a recess located in the latter.
By using the tweezers outfitted according to the invention, it is possible to hold the strip-shaped or thread-shaped material, for example, a polishing strip located inside the oral cavity, without difficulty so that a strip, which can also be made from metal, can be moved back and forth in the gap between two adjacent teeth or on the lateral surface of a tooth in order to polish the surface. The tweezers make it possible to hold the strip-shaped or thread-shaped material without difficulty by means of the clamping elements without the material, e.g., the polishing strip, being bent by the cooperating clamping elements. Strips of half-width (2.5-3 mm) can be introduced into the interdental space below the contact point of adjacent teeth and can be moved without difficulty in the longitudinal direction of the strip and also transverse to the strip, so that every point on the tooth can be reached by the strip. The working part of the polishing strip or thread can be varied continuously in length (working length) by letting go and then holding again with the tweezers. Therefore, it is not necessary to exchange the strip or thread in the course of a polishing or working process; rather, the entire length of the strip or thread is available for working. Therefore, use of the tweezers according to the invention also makes it possible to economize on strips or threads in dental practice.
In a further development of the invention, the clamping elements are constructed as cylinders, preferably with circular cross section, which are arranged axially parallel to one another. They can be fastened to the inner side of the legs of the tweezers by gluing, soldering or welding. The cylinders can also be flattened toward the outer side of the tweezers. However, the cylinders could also have an elliptical cross section in a section vertical to their axis. The cylinders can also be worked out of the material of the tweezers directly, in which case the clamping elements need not be fastened by special fastening means or by gluing, soldering or welding.
In a further embodiment form, the clamping elements of the tweezers according to the invention can be arranged in such a way that they project above the legs of the tweezers on at least one side. In this way, it can be ensured that the clamping elements have sufficient free length to clamp strip-shaped material over its entire width, so that the strip-shaped material is clamped without being damaged.
Handling is improved in a further development of the invention when the longitudinal axis of the rod-shaped clamping elements encloses an obtuse angle with the longitudinal axis of the legs of the tweezers. However, constructions with an acute angle or right angle can also be used. In poorly accessible locations, the angle can be between 75xc2x0 and 90xc2x0.
In another possible embodiment form of the clamping elements, the latter terminate flush with the longitudinal boundaries of the legs of the tweezers. This embodiment form dispenses with clamping elements projecting over the tweezers.
In order to increase friction between the clamping elements and the strip-shaped or thread-shaped material, it is advisable when the outer surface of the clamping elements has a friction coating, e.g., diamond powder, at least in the area of contact with the strip-shaped or thread-shaped material, as is provided in a preferred embodiment form of the tweezers according to the invention. The parts of the outer surface of the clamping elements which do not come into contact with the strip-shaped or thread-shaped material during the clamping process and the plane end faces of the clamping elements advisably do not have a friction coating and, in particular, are polished.
The arrangement of the clamping elements can be carried out in such a way that in the clamping position of the tweezers the centers of the circular cross sections form corner points of an isosceles right-angled triangle in an imaginary section through the clamping cylinder normal to the axis. The cylinder diameters of the clamping elements provided on tweezers can also differ from one another.
The invention will be described more fully in the following by way of example with reference to the drawing.